In terms of what to expect for compensation, I would honestly expect very little. My last complaint to DL was about a year ago simply asking for ORC - Original Routing Credit - for a diverted flight that received zero earnings of any kind. I escalated and escalated and kept being told they do not offer ORC or credit of any kind for diverted flights. I finally gave up as the ORC would have been a trivial amount anyway. That being said about 6 months before this issue I sent in an email simply informing them of an inoperative IFE screen on a specific aircraft. Didn't ask for anything and got 8500 miles. So, my advice would be to not ask for anything when it comes to complaints unless it is an issue you are entitled to (like refunds for downgrades, etc).
Sadly your experience with the unhelpful and rude FA's is becoming more and more common in air travel. Even sometimes in F we experience lackluster crew.
Also, when sending in an initial complaint you might have more luck keeping it very concise. Just a few sentences expressing your disappointment with the unsatisfactory crew. Then, there is a chance someone at DL might reach out beyond the canned response to find out more info. Most likely if that happens you would be offered compensation for your time. (I know, the venting can feel good though!)
Welcome to FT!